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The db840 8" subwoofer boasts a rigid polypropylene cone and durable Santoprene™ surround built to handle big power over the long run. Polk Audio tests their subs rigorously to ensure that they stand up to sunlight, moisture, and extreme temperature changes.

Match a db sub to a suitable enclosure, and enjoy impressive low-frequency performance rarely found in this price range.

What's a component sub and why would I want one?

A component sub is simply a speaker that's designed to reproduce bass once it's installed in a compatible enclosure. Think about the impact of a movie soundtrack in a big theater or even in your own home HDTV setup. A component sub can add the same kind of power to the music in your car. And a car sub is not all about the boom that you hear on a street corner (although that's cool too) - you can pair a component sub with your choice of enclosure to get bass just the way you like it, from tight and punchy to fat and loose. And once you experience music in your car with a well-tuned subwoofer, you'll never go back.

Product Research

Features

Polypropylene Cone: The cone is made with polypropylene, which
provides durability while being lightweight and rigid. The cone is supported by
a vented cone/coil coupler, which stiffens the cone for greater mechanical
stability and lower distortion.

Santoprene
Surround: The Santoprene surround is resistant to extremes in temperature,
humidity, and exposure to sunlight for excellent long term reliability.

Triple-vented Kapton Voice Coil
Former: Triple venting of the 4-layer Kapton Voice Coil Former, Cone/Coil
Coupler and Pole Piece contribute to the high power handling and reliability of
the db Series subs.

Break-In Period: Polk db subwoofers will achieve even greater
performance once they are thoroughly broken-in. To break in a new db Sub, play
music through it for 20 to 30 hours at moderate levels.

Enclosure Compatibility

Recommended Sealed Box Volume: Polk recommends
mounting this woofer in a sealed enclosure made out of 3/4" MDF with an internal
volume of 0.35 cu/ft.

Recommended Ported Box Volume: Polk recommends a ported enclosure made out of 3/4" MDF with an
internal volume of 0.60 cu/ft using a 3" diameter x 11" long port.

Recommended Bandpass Box Volume: Polk recommends a bandpass enclosure
made of 3/4" MDF with a total internal volume of 0.90 cu/ft. The bandpass box
should have a 0.40 cu/ft sealed rear chamber and a 0.50 cu/ft ported front
chamber with a 4" diameter x 12" long port.

Our Product Research Team

At Crutchfield, you'll get detailed, accurate information that's hard to
find elsewhere. That's because we have our own in-house Product Research
team. They verify what’s in the box, check the owner's manual, and record
dimensions, features and specs. We stay on top of new products and technologies
to help people make informed choices.

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Excellent

I installed this woofer to replace a damaged one in a Tahoe. Installation was easy. After install I had much better base than the factory speakers. I had to turn the base down a little on the head unit. Excellent speaker for the money.

No Longevity

I've got 21 drivers in my ride and nine of them are Polk. I was immediately Impressed with
the tightness of this 8" sub and that is what I wanted: Good tight bass without the teeth-
rattling experience. Was disappointed with the frequency response as I was hoping to hear
the upper bass sound that I got from the self-powered Bazooka that this replaced. My fault in
the sub/amp selection.
Mounted in a non-ported, .3c in. enclosure and driven by a Profile sub-amp. Unfortunately,
the sub developed the typical buzzing of the VC after about two years. Looking for another
one now.

A different use for the sub

Unlike most everyone else who will buy this subwoofer, I used mine to upgrade the sub in my LSi15 home speakers. It's an easy upgrade that smooths and deepens the bass output of the 15's. I now feel as though there is enough bass for music without using a seperate powered sub.

Polk Audio db840

I have a bone stock 1995 300ZX 2+2 and wanted to keep the interior that way. I had to "hide" a subwoofer and I had been looking around for something that would fit the limited space I had to work with. I thought for certain that by going with an 8" sub, I'd be compromising the quality but I was ever wrong!. This sub fit perfectly in the small area behind the rear hatch panels and sounds incredible. I would recomend this product to anyone looking for quality sound-regardless of the space they have to work with.
Don
Bedminster, Pa

Very good "musical" bass

Installed this sub into a custom made enclosure built in the center console of a Jeep Wrangler. At 8" it adds nice musical low-end, no thumping heard from a mile away but that is what I wanted. I am feeding with a 200W Rockford Fosgate amp and it seems to really appreciate the power since the sensitivity is pretty low. The enclosure is a little over .3 cu ft but stuffed so virtually close to the recommended .35 cu ft and sounds great. Perfect sub for adding musical low-end to a vehicle.

Polk Audio db840

Very good. I mounted these bad boys in old enclosure, put behind the back seat in my daughters' 73 vw convertible and these things really move some air. I have a Kicker amp in bridge mode supplying the power and it seems to really work well. - Rob

Very Nice!

This is my first subwoofer, and I am very impressed! I didn't have much room, so I got this 8" sub and a custom Q-Logic enclosure for my truck. (My truck is a Dodge Dakota.) I already had Polk db's for my main speakers, so I went with Polk db for the sub too. It really adds the depth I was looking for to fill out my music. It really fills out the low end very nicely! With this sub as part of my system now, I was able set the amp for the main speakers to high pass, relieving them of the burden of having to produce the deep bass. I notice that I can turn the overall volume of my system up louder now. And, it stays clear too! I am very happy!